Pertanika Vol. 7 No. 1 April 1984
PERT-0235-1984
Bromination of 2,5-dimethoxybenzaldehyde
F.B.H. AHMAD and J.M. BRUCE
Keywords
2.5-Dimethoxybenzaldehyde; bromination reaction.
Summary
Bromination of 2,5-dimethoxybenzaldehyde (1) gives 4-bromo-2,5-dimethoxy-benzaldehyde (2)
and not 6-bromo-2f5-dimethoxybenzaldehyde (3) as previously reported by Rubenstein (1925). It
appears that the conjugation of the carbonyl group with the ortho methoxy group (as structure 4)
does not control the orientation of this bromination reaction. A series of reactions which confirm
the structure of the bromination product will be discussed.
PERT-0236-1984
Soil loss and erosivity index of Padang Besar soil series (Petroferric Tropudult)
I: Possible application of Cate-Nelson methods, Anderson-Nelson method and simplified ANOVM
for the determination of critical value
Goiikahjoo and Jamaltalib
Keywords
Soil loss; erosivity index; critical value.
Summary
Knowledge of the critical value for soil erosion data is useful in terms of soil conservation and
management. An experiment was carried out in Universiti Pertanian Malaysia on Padang Besar
soil series (Petroferric tropudult). The bare plot soil loss and rainfall characteristics were
determined after every storm for a year. Soil loss and erosivity index (K.E. > 10) were fitted with
different models. Various approaches were then adapted to study their suitability in obtaining
critical values for soil erosion data. In this paper, an example showing the application of
techniques and their principles is given. Results indicate that all the four procedures provide
similar critical values despite their different principles. It is further showns that new Cate-Nelson
technique and simplified ANOVM (a- 0.001) result in higher R (0.84**) than the best quadratic
model (R2 = 0.54**). However, due to the principle of obtaining critical values for soil erosion
data, it may suffice to use simplified ANOVM (Ct = 0.001).
PERT-0237-1984
Development of Basic Mechanical Tests for Malaysian Bamboos
Abang Abdullah Abang Ali
Keywords
Mechanical test standard; bamboo; strength properties.
Summary
Bamboo has found various applications, especially to the rural people, but its potential as an
engineering material has not been fully realised because of a lack of knowledge of its strength
properties. In the absence of -a commonly accepted standard for the mechanical testing of
bamboo, a procedure for basic strength tests was developed. Results for the strength properties
of Bambusa vulgaris, locally known as Buluh Minyak, are presented.
PERT-0238-1984
Convergence Proof of Some Generalised Backward Differentiation (GBDF) Methods to Solve the
General Second Order Ordinary Differential Equations (ODE)
Mohamed Bin Suleiman
Keywords
Convergence; stiffness; Adams-Moulton methods; Generalised Backward Differentiation
methods; Direct Integration methods; consistency; stability
Summary
Methods for the solution of the general second order ODE are discussed. Stiffness and
convergence are also defined. Finally proof of convergence is given for certain cases of the
GBDF methods for stiff problems.
PERT-0239-1984
Identification of a Potyvirus Infecting Groundnut, Arachis hypogeae L., in Malaysia
Norani Abdul-Samad
Keywords
Legume virus; potyvirus; electron microscopy.
Summary
A virus disease showing leaf mottling in groundnuts, Arachis hypogeae cv. V 13, was observed in
experimental plots at the Universiti Pertanian Malaysia, Serdang, West Malaysia, in 1982. The
virus is sap-transmissible and can also be transmitted by the aphid, Aphis craccivora Koch, in a
non-persistent manner. The host range is narrow. It produced chlorotic local lesions in
Chenopodium amaranticolar Coste & Reyn and systemic chlorotic lesions in Vigna sinensis Sav.
Electron microscopic examination of virus infected groundnut leaves revealed'the presence of
long flexuous particles about 800 nm in length and pinwheel inclusions in tissue sections;
therefore, the virus belongs to the potyvirus group.
PERT-0240-1984
A Correlational Study of Achievement Motivation and Pupils' Performance in the Standard Five
Assessment Examination From Selected Schools in Selangor.
Habibah Elias and Atan Bin Long
Keywords
Achievement motivation; performance in examination; correlations..
Summary
The performance of pupils in the Primary Five Assessment Examination was examined in relation
to a number of variables namely achievement motivation, socio-economic status, intelligence,
area of residence, school milieu and parental encouragement to assess the correlation between
them. The subjects were 90 pupils selected from 40 primary schools in Selangor and represented
the Chinese, Malays and Indians; Individual interviews were conducted by the researcher.
Subjects were asked to answer questionnaires, the Thematic Apperception Test, and the Raven's
Progressive Matrices. The results showed that achievement motivation correlated highly with
performance in the stated examination. The other variables which showed significant correlations
with performance were socio-economic status, intelligence, school milieu and parental
encouragement.
PERT-0241-1984
Nitrite Content of Some Foods in Malaysia
A. S. Babji, Aishah, S And Aminah, A.
Keywords
Nitrite content; foods; Malaysia.
Summary
Nitrate and nitrite are additives commonly used in meat curing for improvement of colour and
flavour and as protection against the growth of Clostridium botulinum. Nitrite can combine with
secondary amines to form nitrosamines, the source of controversy in the use of nitrite as food
additivies. Analysis of nitrite levels in several foods suspected of containing added nitrite was
carried out Levels of residual nitrite in meat products were in the range of 14 — 54 ppm,
processed pickled fruits and vegetables 7 — 81 ppm and salted dried fish 11—38 ppm. Results
indicate the level of residual nitrite in most foods is below the permissable level of 200 ppm.
PERT-0242-1984
An Investigation of the Chemical Composition of Precipitation in and around Kuala Lumpur
C. K. Lee and K. S. Low
Summary
Individual rain event samples were collected at three sites in and around Kuala Lumpur from May,
1982 to May 1983. The samples were analysed for pH, anions (sulphate, nitrate, chloride and
fluoride) and cations (calcium, magnesium, sodium and potassium). Correlation and regression
analyses indicated that the major anions appeared to be more closely associated with the cations
than the hydrogen ion. Pollutants from both natural and anthropogenic sources appeared to have
contributed to the chemical composition of precipitation.
PERT-0243-1984
Performance Evaluation of a Simple, Locally-Designed Padi Thresher
Wan Ishak Wan Ismail, Mohammad Mohd Lassim and Ahmad Husni Mohd Haniff.
Keywords
Threshing capacity; threshing efficiency; product purity.
Summary
Performance evaluation studies of a padi thresher designed at Universiti Pertanian Malaysia
Cawangan Sarawak indicated that it was a high capacity thresher. Using manual labour, it was
capable of threshing padi at a rate of 45 to 68 kg/hr. The skill and the physical power of the
operator determined the actual rate of threshing. However, when engine powered, threshing was
accomplished at a constant 121.3 kg/hr. Thresing efficiency was found to be 87% or higher and
product purity was 79% or higher. The possibility of this thresher being adopted for use by padi
farmers is good because there is a marked increase in output per man-hour over manual
threshing. In addition, it is cheap, light and easy to fabricate.
PERT-0244-1984
The flowering, pollination and hybridization of groundnuts (Arachis hypogaea L.)
E. S. LIM and J. S. GUMPIL
Keywords
Flowering; pollination; hybridization; groundnuts.
Summary
The flowering pattern, emasculation and pollination of locally grown groundnuts were studied.
Flowering generally occurred between 0645 to 0900 h with a half hour delay on dull days. Anther
dehiscence occurred in the bud about one hour prior to blooming. Pollen tube growth was
approximately 1 cm per hour and fertilization was estimated to take place 5 to 6 hours after
pollination. There was no improvement in pod set following tripping of the flowers although it was
found that assisted pollination improved peg formation over natural self-pollination.
Emasculations can be carried out either using forceps or suction on the afternoon prior to the day
of anthesis without any detrimental effect on the success of cross-pollination. Some crosscombinations and parents were capable of higher success in cross-pollinations than others
PERT-0245-1984
Quadrature Method for an Autonomous Ordinary Differential Equation
Harun Budin
Keywords
Autonomous; differential equation; uniqueness; spectrum.
Summary
A quadrature method is used to obtain uniqueness results for an autonomous nonlinear ordinary
differential equation. This method enables us to give a necessary and sufficient condition for a
unique solution when the nonlinearity is convex. The technique is then used to determine
supremum of the spectrum for the problem with convex nonlinearity.
PERT-0246-1984
A Geometric Look at Repeated Measures Design with Missing Observations
Ahmad Bin Alwi and C.J. Monlezun
Keywords
Repeated measures design; subspaces; noncentrality parameters; orthogonal: orthonormal
basis;.
Summary
In this paper, we will provide a geometric view of Repeated Measures Design for unequal number
of subjects per treatment that has missing observations. For our geometric development we
restrict our design to three levels of factor A and four levels of factor B. The purpose of this paper
is to develop a test statistics for hypotheses of interest i.e. no main effect A, no main effect B, and
no AB interaction.
PERT-0247-1984
Pembuangan Tanin Dalam Jus Gajus
Ahmad Ismail Dan Mamat @ Shafie Embong.
SUMMARY
The objective of this work was to remove tannin from the cashew juice so that it could be used as
a drink which contained a high concentration of vitamin C. The substances used for this purpose
were polyvinylpyrrolidone (PVP), albumin and bentonite. The variable parameters were
concentration, temperature and pH. The three absorbents used were able to reduce tannin
concentration in the juice. Of the three absorbents, PVP was most effective followed by albumin
and bentonite. The optima concentrations of the absorbents for removal of tannin were 0.4
percent for PVP and albumin and 24 percent for bentonite. Maximal pH for the extraction was 8.5
for PVP, 9.5 for albumin and 10.0 for bentonite. Removal of tannin increased slightly with the
increase in temperature. A stirring time of 5 minutes was sufficient for PVP and albumin.
However, for bentonite, 30 minutes were needed to obtain the maximum extraction. The use of
bentonite caused an increase in the pH of the juice. However, the Vitamin C content decreased
during the removal of tannin especially when oentonite and albumin were used.
PERT-0248-1984
Structure of Mangrove Vegetation at Siar Beach, Lundu, Sarawak.
Saberi Bin Othman
SUMMARY
A study of mangrove vegetation was conducted at Siar River estuary, Lundu, Sarawak. The
zonation of plants is described based upon the ordination of stands. The relation between the
zonation of plants at this mangrove forest with other mangrove vegetation is also discussed.
PERT-0249-1984
A Survey on Computer Utilisation in Malaysia
Mohd. Zain B. Mohamed and Han Chun Kwong
Keywords
Computer utilisation; computer installations; computer applications; data processing; data
processing personel.
SUMMARY
Government departments and agencies, banking and finance, and distribution companies
represented the major computer users (54%) in Malaysia ini 1982. Most of the computers were
used for routine applications such as general ledger, accounts receivable, accounts payable,
payroll, invoicing, inventory control, and sales analysis and reporting. The majority of the
computers (57%) were operated for less than 300 hours per month.
PERT-0250-1984
COMMUNICATION I
Nutritional Requirements for Reproduction of Micromus tasmaniae Walker (Neuroptera:
Hentervbiidae)
Summary
A laboratory experiment was conducted to determine whether it is males or females of Micromus
tasmaniae Walker that require nutrients other than sugar to mate and promote egg development
Four categories of diets were tested on newly emerged adults. The treatments were differentiated
based on whether or not male or female or both sexes were deprived of live prey (Myzue
persicae Sulzer) before. Egg counts indicated that oviposition occurred mainly when females had
access to aphids prior to pairing. Depriving the males of aphids did not alter the incidence of
oviposition. It is necessary to provide females with live aphids prior to mating to be able to rear
them.
PERT-0251-1984
COMMUNICATION II
The Accumulation of Heavy Metals in Hydrostemma Motleyi Hook. f. Mabberlay and Hydrilla
verticillata Casp.
Summary
The uptake of neavy metals (copper, zinc, nickel, cadmium and chromium) by Hydrostemma
motleyi (Hook.f) Mobberlay and Hydrilla Verticillata Casp. was studied. The uptake generally
increased with increasing metal concentrations. The enrichment factor which relates the metal
content in plants to the metal content in cultivation media generally decreased with increasing
metal concentrations. Antagonistic action was observed when Hydrostemma motleyi was
cultivated in mixed solutions of copper, zinc and nickel. For Hydrilla verticillata, synergistic effect
was observed at low concentration of the mixed solution, but at higher concentrations, the effect
was reversed. Metal accumulation appears to be species specific. Hydrilla verticillata exhibited a
higher tolerance and accumulation capacity for heavy metals than Hydrostemma motleyi. It has
the potential of being an indicator species for metal pollution in water.
PERT-0252-1984
COMMUNICATION III
A Case of Feline Panieukopenia in Malaysia Confirmed by Electron Microscopy
SUMMARY
A typical case of feline panieukopenia in an 18 month-old domestic cat is reported. The disease
was characterised clinically by anorexia, depression, diarrhoea and dehydration. Typical
pathological changes of severe villous atrophy and erosion of the small intestinal epithelium were
observed. Electron microscopic examination of the faeces revealed the presence of particles
resembling parvovirus.